Take a stroll through this 1940 Chevrolet Truck document. There is at least one good artist rendering of a cab interior view from the passenger side with door open that may be of some help. Also saw a rendering of a COE cab interior, but that's a touch different than the rest of the Chevy truck line.
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~ Dan
1951 Chevy 3 window 3100
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"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)